The FAA alleges that during inspections in Boston, San Francisco, Denver and Chicago, the FAA discovered at least 120 instances in which the carrier failed to comply with the regulations. Almost all of the alleged violations involved failing to provide the pilot in command with accurate information about hazardous materials aboard the aircraft, including the location of the materials on the aircraft; the materials’ type, quantity, weight, proper shipping name, identification number and hazard class; dates of the flights; and confirmation that no damaged or leaking packages had been loaded onto the aircraft.

Further, the FAA alleges that on two separate occasions, United improperly accepted hazardous materials for air transportation. Additionally, the carrier allegedly failed to retain copies of shipping papers.

The alleged violations occurred on domestic and international flights.

“These regulations are intended to keep flight crews and the public safe and we expect airlines to follow these rules to the letter,” said U.S. Transportation Secretary Anthony Foxx.

“Knowing exactly what’s on board the aircraft and where it’s located provides the crew with a better chance of safely handling an emergency,” said FAA Administrator Michael Huerta.

United told the FAA that it has made technological improvements to the pilot notification system and will enhance training for employees who load hazardous materials onto aircraft. The FAA will conduct inspections in early 2015 to assess the results of those changes.

United has 30 days from receipt of the FAA’s enforcement letter to respond to the agency.